Sterilizing apparatus and method



July M, 1953 l, R. LEWIS ET AL STERILIZING APPARATUS AND METHOD FiledJune 30, 1949 I JNVENTORS IRVING R. LEWIS A TTORNEYS' Patented July 14,1953 UNITED STATES PATENT OFFICE STERILIZING APPARATUS AND METHOD NewJersey Application June 30, 1949, Serial No. 102,196

2 Claims.

This invention relates to the heat treatment of articles of essentiallycylindrical contour and, particularly, to an improved method andapparatus for the handling of essentially cylindrical articles in heattreatment thereof in a manner to permit relatively rapid temperaturechanges without damage to the articles. More particularly, the inventionrelates to an improved method and apparatus for the rapid sterilizationof vials, ampules and other containers of the type generally employed inthe sterile packaging of pharmaceutical preparations and the like.

It is of primary importance in the packaging of many pharmaceuticalpreparations, particularly those intended for parenteral injection, thatthe vials, ampules, or other containers employed be thoroughlysterilized prior to carrying out sterile packaging operations. In thepast, it has been customary to sterilize such containers by arrangingthem in covered trays and heating the trays and containers in an oven ata temperature of 250 C. for about two hours, generally with a number oftrays assembled together in a suitable supporting rack. At the end ofthis time, the racks with the still-covered pans are removed to anair-conditioned, dust-free room and allowed to cool to room temperature,a step often requiring as long as six hours. The long cooling time isnecessary because of the slow dissipation of heat from the containerswithin the covered pans, yet it is of primary importance that the pansremain covered since the sterility of the vials or containers wouldotherwise be impaired.

In addition to the objectionably long time required in the foregoingsterilization procedure, it will be evident that there still remains theproblem of maintaining the vials or containers in a sterile conditionwhen transferring them from the pans to sterile cubicles or otherenclosures in which filling operations are carried out. Even when thegreatest precautions are taken, there is considerable risk ofcontamination during this transfer.

An object of the present invention is to provide a new method andapparatus which will permit it the sterilization time to be reduced fromthe usual period of about eight hours to a period of a few minutes; afurther object being to provide a method and apparatus for thecontinuous rapid sterilization of vials or containers as a final step indelivering the same to sterile packaging cubicles whereby the sterilizedcontainers are deposited directly within the cubicles.

These and other objects of the invention will be more readily understoodfrom a consideration of the following specification and accompanyingdrawing in which the various parts of the apparatus are identified bysuitable reference characteristics in each of the views and in which:

Figure 1 is a side elevation of one form of our apparatus with part ofthe structure broken away and in section and with portions of theassemblage diagrammatically shown;

Figure 2 is an enlarged View substantially on the broken line 22 ofFigure 1.

Regarded in certain of its broader aspects the novel method andapparatus for heat treating or sterilizing essentially cylindricalarticles such as vials, ampules, or other containers involvessuccessively feeding articles to be heat treated to one end of anelongated cylindrical tube or chamber while continuously rotating thesame on its axis, applying heat to a portion of the tube or chamberadjacent the feed end thereof, and applying a cooling medium to theremainder of the chamber, and so regulating the feeding of articles tothe chamber and the application of heat and cooling medium thereto as toprovide for discharge of articles from the remote end of the tube orchamber in an essentially cool and thoroughly sterile condition.

One embodiment of the invention is disclosed in the drawing showing theapparatus set up in a conveyor line for delivering vials or ampules 3 toa sterile packaging cubicle 4, and including an elongated cylindricaltube or chamber 5 rotatably supported at the feed end thereof by a driveunit 6 and at the discharge end thereof by a roller support unit I. Thetube 5 is preferably formed of stainless steel, but other heat resistantmaterials having good thermal conductivity can also be employed. Thedischarge end of the tube 5 extends into the cubicle 4, and between thetube and cubicle is provided an essentially gasti ht sealdiagrammatically indicated at 8.

Adjacent the feed end of the tube 5, we have shown a guide member 9adapted to receive the vials or ampules 3 from a suitable conveyor andalign the same with the opening in the tube 5, and means is provided asdiagrammatically indicated by the bell crank feed arm Ill for advancingvials or ampules 3 from the guide member 9 into the tube 5. Means isalso provided, as indicated by the enlarged lower end of the feed armII], for preventing movement of vials into the guide 9 during theforward feed motion of the arm [6.

The inside diameter of the tube 5 should be sufiiciently larger than theoutside diameter of the vials or ampules 3 to permit free rotation ofthe vials or ampules on the inner wall of the tube as the tube rotatesabout its axis. At the same time, it is preferable to provide a minimumamount of clearance between the vials and tube in order to facilitaterapid heat transfer therebetween. A ratio of about 8 to 9 between theoutside diameter of the vials and inside diameter of the tube has beenfound to be satisfactory. It should be noted in this connection that therotary motion of the vials with respect to the tube prevents anyextended period of contact between any one pointon the vial and thetube, thus minimizing the danger of breakage in the vials or ampules dueto excessive localized heating or cooling.

In the adaptation shown in the drawing, the tube is arranged in aninclined position, and when thus arranged it will be apparent that therotation of the tube and the rotation of the vials within the tubeoperates to continuously and slowly advance the vials toward thedischarge end of the tube. In this adaptation of theapparatus, it willthus be apparent that the feed arm it serves merely to deliver vials tothe tube. It is possible, however, to arrange the tube 5 in a horizontalposition in which event the feed arm It would serve not only to delivervials to the tube but also to advance the column of vials therethrough.

Adjacent the feed end of the tube 5 and circumferentially envelopingsaid tube in closely spaced relation thereto is a heating unit i l whichis preferably an electrical unit of either the resistance or inductancetype. range of the unit ll will, of course, depend upon the particularheat treating or sterilizing operation to be performed. In thesterilizing of vials of the type shown in the drawing, it is desirableto employ a heating unit which will raise the vials to a temperature ofabout 700 F. in two to three minutes. It is found that this rapidelevation in temperature of the vials can be effected without an dangerof breakage when the vials are continuously rotated in the tube 5 in themanner previously described.

Means is provided along the remainder of the tube 5 as indicateddiagrammatically by the feed line l2 and valves l3 therein for applyingwater or other cooling medium to the outside of the tube 5. Suitablereceptacles M are provided below the tube 5 to catch the cooling medium,and the tube is preferably provided with spaced flanges l5 for limitingmovement of the cooling medium longitudinally of the tube andfacilitating collection of the medium by feed receptacles. A pluralityof valves l3 are preferably employed to provide a degree of flexibilityin control of the rate of cooling of the tube and vials arrangedtherein. It will, of course, be apparent that cooling may be effected bymeans of a cooling coil or jacket integral with the tube itself, and itis to be understood that the cooling means shown in the drawing isintended to represent diagrammatically any suitable cooling means.

As it becomes necessary from time to time to clean the tube 5, it isadvisable to provide means as indicated by the spaced heater units orburners it for heating the entire length of the tube 5 for sterilizationthereof after cleaning. It will, of course, be understood that anyarrangement of a heating element or elements longitudinally of the tubecan be employed for this purpose, and it is to be understood that theburners it are intended The size and heat n merely as a diagrammaticindication of any suitable heating means.

Since intermittent cleaning of the tube 5 requires that the tube beeasily removed from the apparatus, we preferably employ in the rollersupport unit I merely a pair of rollers I! grooved to engage a collar orflange I8 on the tube 5. The drive unit 6 as more clearly shown inFigure 2 of the drawing employs a pair of drive rollers 19 grooved toengage a collar or flange 28 on the tube 5. In order to ensure positiveengagement between the drive rollers and the tube, we provide a thirdgrooved roller 2i supported in a bracket or housing 22 hinged, as at 23,to the body of the drive unit 6, and having a locking engagement as at2d with said drive unit to facilitate easy release of the tube forremoval thereof from the apparatus. Any suitable drive means such, forexample, as a chain 25 may be employed for driving the rollers Hi. Itshould be noted in this connection that when employing the apparatus forthe sterilization of vials or ampules in the manner shown, it isgenerally desirable in prac tice to employ a number of sterilizing tubeswith one or more of such tubes registering with each of a number ofcubicles d. In such a set-up, it will be apparent that a central drivecan be employed to actuate the feed rollers of all of the units.Alternatively, of course, each unit can be provided with an individualelectrical motor or other source of power. In sterilizing vials orampules with the apparatus disclosed, it has been found that rotation ofthe tube 5 at a rate of about 18 R. P. M. produces satisfactory resultswhen arranged on an incline of about 1 inch per foot and that elevationof temperature of the vials to 790 F. within about two to three minutesand cooling to room temperature within about six minutes renders thevials thoroughly sterile and pyrogen-free.

As evidence of the reliability of the apparatus in handling andsterilizing vials without damage, continuous rotation of vials within atube for a period of thirty minutes (more than three times the normaltime that a vial will remain in the tube) gave no indication whatever ofdamage due to abrasion. In no instance has there been evidence ofbreakage of vials or ampules due to the rapid heating and cooling asmight be expected if the vials were rapidly heated and cooled instationary contact with a supporting element.

The cubicle may be of any conventional type such as those normally usedin the packaging of pharmaceutical products, and is preferably providedwith flexible hand insert members 25 for receiving the hands of anoperator. Vials or ampules 3 may be picked up by the operator as theyemerge from the tube 5 or may be deposited in a suitable conveyor suchas the inclined trough 2i for carrying the same to a storage area 28within the cubicle.

It is, of course, to be understood that every effort is made to ensuresterile conditions within the cubicle, and in this connection it will beevident that any air entering the cubicle through the tube 5 isautomatically sterilized in passing through the zone heated by theelement Ii. If a positive pressure is desired within the cubicle,however, means may be provided as indicated by the blower 29 forintroducing sterile air to the cubicle. In practice, it is found thatbest results are obtained when the pressure within and without thecubicle is essentially the same.

With a tube 5 of particular length and diameter, it is possible byappropriate regulation of the speed of rotation of the tube, rate ofadvance of articles through the tube, and amount of heat and coolingmedium applied to heat treat or sterilize a number of different sizes ofvials, ampules or other cylindrical articles. For best results, however,the diameter and length of the tube should be selected to meet therequirements of the particular size article to be treated.

Throughout the disclosure, special emphasis has been placed on theadaptation of our apparatus for the sterilization of vials, ampules, andthe like, but it is to be understood that it is equally adapted fortempering, annealing, and other heat treating operations in which rapidcontrolled heating followed by rapid controlled cooling of articles isdesired.

Various changes and modifications in the apparatus herein disclosed willoccur to those skilled in the art, and to the effect that such changesand modifications are embraced by the appended claims, they areunderstood to constitute'part of our invention.

We claim:

1. The method of delivering cylindrical containers in a sterilecondition to a sterile filling and sealing zone that comprises advancinga co-axially arranged series of cylindrical containers successivelythrough a heating zone and a cooling zone registering with said sterilefilling and sealing zone while providing support for each of saidarticles along a line of contact extending longitudinally thereof whichis continuously 6 shifting about the cylindrical periphery of saidarticle.

2. An apparatus for delivering essentially cylindrical containers to asterile filling and sealing cubicle while simultaneously sterilizingsaid containers, said apparatus comprising conveyor means for advancingcylindrical containers in end to end relationship, in combination with asterilizing unit comprising an elongated and rotatably supported tubehaving one end registering with said conveyor means and the other enddisposed within said sterile cubicle, means for heating said tubeadjacent the first named end thereof, means for applying a coolingmedium to other portions of said tube, and the inner surface of saidtube having a smooth and uninterrupted cylindrical contour of uniformdiameter throughout the length of said tube, whereby the rotation ofsaid tube causes the cylindrical containers passing therethrough to rollcontinuously and circumferentially with respect to the inner surface ofsaid tube.

IRVING R. LEWIS. DOUGLAS M. McBEAN.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,446,857 Peiter Feb. 27, 1923 1,642,577 Carson Sept. 13, 19272,056,526 Kennedy Oct. 6, 1936

1. THE METHOD OF DELIVERING CYLINDRICAL CONTAINERS IN A STERILECONDITION TO A STEILLEE FILLING FILLING AND SEALING ZONE THAT COMPRISESADVANCING A CO-AXIALLY ARRANGED SERIES OF CYLINDRICAL CONTAINERSSUCCESSIVELY THROUGH A HEATING ZONE AND A COOLING ZONE REGISTERING WITHSAID STERILE FILLING AND SEALING ZONE WHILE PROVIDING SUPPORT FOR EACHOF SAID ARTICLES ALONG A LINE OF CONTACT EXTENDING LONGITUDINALLYTHEREOF WHICH IS CONTINUOUSLY SHIFTING ABOUT THE CYLINDRICAL PERIPHERYOF SAID ARTICLE.